Insect ID – is this a Tussock Moth?

Is this Orgyia leucostigma – White-marked Tussock Moth?

Homeowner says there are thousands of them on her garage and trees (haven’t confirmed type of tree she has them on, she thought it might be an Ash tree).

She would like to know if she needs to do something for treatment? Should they be concerned about damage?





  1. Yes—caterpillar of the white-marked tussock moth. Overall these can be very common in mid-to-late summer and usually don’t cause much damage. However, given the numbers of them in this case, they could potentially cause some significant defoliation.

    An important consideration would be the size. At maturity, these caterpillars only get to be ~1.25 inches long (body length; don’t measure the long black filaments). If they’re close to that size, they’re almost done feeding and any damage is already done (so treating won’t really do much). If smaller (such as 3/4″ long), they’ll be feeding for a while longer. If needed, they could be controlled with a spray of soapy water, insecticidal soap, or pyrethrins. Conventional spays from the hardware store/garden center labelled for caterpillars on landscape trees/shrubs would also work, if needed. One could also knock them into a container of soapy water, but wear gloves as the tufts of “hair” on the body can irritate skin of sensitive individuals.


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